I've bent a couple upper arms while errmm... jumping my first wagon (did the same in a few Hornets I drove around the back 40)
Okay now we're getting to the bottom of the issue
If we're talking jumping, off roading or anything of that nature, my lift will not work. Absolutely building some longer tubular control arms is the way to go, and using some coilovers or something.
Not to go off on another rant or sounding like I am on my soap box but here it goes...
I have worked in shops and worked in aftermarket parts and in a machine shop so I have seem many sides of the automotive world. The thing that has to happen when a project is started is the vehicle owner needs to be very real with themselves. You have to know what you are looking to do with the vehicle and how much you have to spend and how much effort you have to put into the project. Trying to sell parts to a person that wants to go hardcore desert racing but also drive the car to work is going to have to compromise.
I built my setup because I wanted to prove a concept, retain the IFS and have a daily drivable vehicle. I think I have obtained that... minus a few kinks that need worked out.
Sorry for the rant but I get frustrated on behalf of others who walk down a path and run out of money or end up with a vehicle that isn't what they want.
Point being. I think my design is durable enough to be a basis for your project "Jumping Wagon" (I like how that sounds) but I would work on tubular control arms, coil overs, and you will need to find some longer CVs. If you are in AK I would even be willing to help you build it. This was my original idea for my car but I got "real" with myself and decided I wanted a driver and I didn't have the time or desire to have a dedicated off road eagle.
Anyway. Just some thoughts for the day.